DE102013224120A1 - METHOD AND DEVICE FOR CONTROLLING SWITCHING IN A MULTI-MODE DRIVE TRAY SYSTEM - Google Patents

Abstract

One method of operating the powertrain system includes performing a transmission shift between an initial electrically variable transmission range (EVT range) and an EVT target range. Gear shifting includes entering a three speed freedom mode that controls the speed of a second torque machine to synchronize the speed of an on-coming clutch associated with the target EVT range and simultaneously controlling the speeds of a first torque machine and an engine to achieve a preferred speed of the output member of the transmission. The gear shift further includes controlling torque output from the first torque machine in response to an output torque request and activating the on-coming clutch after synchronizing the speed of the on-coming clutch. Following the gear shift, the powertrain system is operated in the EVT target area.

Description

TECHNICAL AREA

This disclosure relates to dynamic system controllers associated with multi-mode powertrain systems employing multiple torque-generative devices.

BACKGROUND

The statements in this section are only background information related to the present disclosure. Consequently, such statements should not constitute acknowledgment of the state of the art.

Powertrain systems may be configured to transmit torque output from a plurality of torque actuators through a torque transfer device to an output member that may be coupled to a driveline. Such powertrain systems include hybrid powertrain systems and extended range electric vehicle systems. Control systems for operating such powertrain systems operate the torque actuators and apply torque-transmitting components in the transmission to transmit torque in response to operator-commanded output torque requests, taking into account fuel economy, emissions, driveability, and other factors. Exemplary torque actuators include internal combustion engines and non-combustion torque machines. The non-combustion torque machines may include electric machines that operate as motors or generators to generate torque input to the transmission independently of a torque input from the engine. The torque machines, in a process referred to as recuperation operation, may convert kinetic energy of the vehicle transmitted by the vehicle driveline into electrical energy that is storable in an electrical energy storage device. A control system monitors various inputs from the vehicle and the operator and provides for functional control of the hybrid powertrain, control of transmission operating range and gearshift, control of the torque actuators, and control of electrical power exchange between the electrical energy storage device and the torque actuators Includes outputs of the transmission, which include torque and speed to manage.

Known electrically variable multi-mode transmissions (EVTs) may be configured to operate in one or more hard landing areas, one or more electric vehicle (EV) areas, and one or more electrically variable transmission (EVT) areas. Known circuits between a first and second EVT area occur at a synchronous speed point. Known circuits are implemented using one of the EVT regions to slow down the engine speed to a desired transmission gear ratio and thus to effect a shift that includes synchronous activation of an on-coming clutch. Transmission output torque may as well be controlled during this type of shift, but the shift time may be long and require changes in engine speed that may be noticeable to a vehicle operator. In addition, it may be desirable to switch between two EVT modes while maintaining a constant speed of the engine to impart a vehicle feel perceived as supple by an operator. For example, during a transition from an EV travel mode to an engine-on mode operation at moderately high vehicle speeds, the engine is started in a first, lower EVT range, e.g. A range with input power split, where the transmission immediately transitions to a second higher EVT range having a combined power split region to effect more efficient operation at higher vehicle speed. The required maximum torque from a first torque machine may be defined at a synchronous point for transition from an input-split region to a combined-split region because the first torque machine in the combined-power-split arrangement has torque from the engine and torque from a second torque machine must counteract.

SUMMARY

A powertrain system includes a multi-mode transmission configured to transmit torque among an engine, first and second torque machines, and an output member in one of a plurality of transmission ranges. A method of operating the powertrain system includes performing a gear shift between an electrically-variable Initial transmission range (EVT range) and an EVT target range. Transmission shifting includes transitioning to three speed degrees of freedom operation, which is controlling the speed of the second torque machine to synchronize the speed of an oncoming clutch associated with the EVT target range, and simultaneously controlling the speeds of the first torque machine and the engine includes to achieve a preferred speed of the output element of the transmission. The transmission shifting further comprises controlling the torque output from the first torque machine in response to an output torque request, and activating the on-coming clutch after synchronizing the speed of the on-coming clutch. Following transmission shifting, the powertrain system operates in the EVT target area.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments will now be described, by way of example, with reference to the accompanying drawings, in which:

1 a multi-mode powertrain system including an internal combustion engine, a transmission, and a driveline, according to the disclosure;

2 a control scheme for effecting a change of a target transmission range, comprising applying a transmission operating range having three degrees of freedom, according to the disclosure; and

3 Operating parameters associated with the powertrain system of 1 associated with the control scheme of 2 is executed, illustrated in accordance with the disclosure.

DETAILED DESCRIPTION

Referring now to the drawings wherein the foregoing is intended solely for the purpose of illustrating certain example embodiments and not for the purpose of limiting the same 1 a multi-mode powertrain system including an internal combustion engine (engine) 12 , a multi-mode gearbox (gearbox) 10 , a high-voltage electrical system, a driveline 90 and a controller 5 includes. The gear 10 is mechanical with torque actuators that the engine 12 and first and second torque machines 60 respectively. 62 include, coupled and is designed to torque between the engine 12 , the first and second torque machines 60 . 62 and the final drive 90 transferred to. As illustrated, the first and second torque machines are 60 . 62 Electric motors / generators. The final drive 90 For example, a differential system that enables a rear-wheel drive vehicle configuration or a transaxle system that provides a front-wheel drive vehicle configuration may be included.

The engine 12 may be any suitable combustor and includes a multi-cylinder internal combustion engine that is selectively operable in various states to apply torque via an input member 14 on the gearbox 10 and may be a spark-ignition or compression-ignition engine. The engine 12 includes a crankshaft connected to the input member 14 of the transmission 10 is coupled. Power coming from the engine 12 that is, speed of the engine and torque of the engine may be due to the placement of torque consuming components on the input member 14 between the engine 12 and the transmission 10 , z. B. a torque management device or a mechanically driven hydraulic pump, from the input speed and the input torque in the transmission 10 differ. The engine 12 is configured to perform auto-stop and auto-start operations in response to operating conditions while the powertrain is in continuous operation. The controller 5 is designed to be actuators of the engine 12 and thus combustion parameters including intake air flow rate, spark timing, injected fuel amount, fuel injection timing, EGR valve position for controlling the flow of recirculated exhaust gases, and intake and / or exhaust valve timing and phasing on engine equipped engines. Thus, the speed of the engine may be controlled by controlling combustion parameters including air flow torque and spark induced torque. The speed of the engine may also be controlled by controlling engine torques of the first and second torque machines 60 . 62 Reaction torque at the input element 14 is controlled.

The illustrated gearbox 10 is an electro-mechanical two-mode transmission with combined power split, the two planetary gear sets 20 and 30 and three engageable torque transmitting devices, ie clutches C1 52 , C2 54 and C3 56 , includes. The two modes of operation relate to power split operating modes that include an input split split mode of operation and a combined split split mode as described herein. Other embodiments of the transmission are contemplated, including those having three or more power split modes of operation. The gear 10 is designed to torque between the engine 12 , the first and second torque machines 60 . 62 and an output element 92 in response to an output torque request. The first and second torque machines 60 . 62 In one embodiment, motors / generators use electrical energy to generate power and counteract torque. The planetary gear set 20 includes a sun gear element 22 , a ring gear member 26 and planet gears 24 which are coupled to a carrier element. The carrier element supports the planet gears 24 rotatable, in intermeshing relationship with both the sun gear member 22 as well as the ring gear member 26 are arranged, and is provided with a rotatable shaft member 16 coupled. The planetary gear set 30 includes a sun gear element 32 , a ring gear member 36 and planet gears 34 which are coupled to a carrier element. The planet wheels 34 are in meshing relationship with both the sun gear member 32 as well as the ring gear member 36 arranged, and the support member is connected to the rotatable shaft member 16 coupled.

As used herein, clutches refer to torque transmitting devices that can be selectively applied in response to a control signal. Each of the clutches may be any suitable torque transmitting device, including, for example, a single or composite plate clutch or a single or composite plate package, a one-way clutch, a belt clutch or a brake. In one embodiment, one or more of the clutches may include one way clutches or selectable one way clutches. A control circuit is configured to control clutch states of each of the clutches, including activating and deactivating each of the clutches. In one embodiment, the control circuit is a hydraulic circuit configured to control clutch states of each of the clutches, wherein hydraulic pressure fluid is supplied by a hydraulic pump provided by the controller 5 can be functionally controlled. Clutch C2 54 is a rotating clutch. Clutches C1 52 and C3 56 are brake devices attached to a gearbox 55 can be determined.

A high voltage electrical system includes an electrical energy storage device, e.g. A high voltage battery (battery) electrically coupled to a power converter module via a high voltage electrical bus, and is configured with suitable means for monitoring electrical power flow, including means and systems for monitoring the electrical current and voltage. The battery may be any suitable high voltage storage device for electrical energy, e.g. A high voltage battery, and preferably includes a monitoring system that provides a measure of the electrical power supplied to the high voltage electrical bus that includes voltage and electrical current.

The first and second torque machines 60 . 62 In one embodiment, three-phase motor / generator machines, each having a stator, a rotor and a speed sensor, e.g. As a resolver includes. The motor stator for each of the torque machines 60 . 62 is at an outer portion of the gear box 55 and includes a stator core with coiled electrical windings extending therefrom. The rotor for the first torque machine 60 is supported on a Nabenplattenzahnrad which is mechanically attached to a rotating member which is connected to the sun gear 22 of the first planetary gear set 20 is coupled. The rotor for the second torque machine 62 is firmly attached to a rotating element that is connected to the sun gear 32 of the second planetary gear set 30 is coupled.

The starting element 92 of the transmission 10 is rotatable with the final drive 90 connected to output power to the driveline 90 to be transmitted in this embodiment to one or more vehicle wheels via a differential gear, a transaxle assembly or other suitable means. The output power at the output element 92 is characterized in terms of an output speed and an output torque.

The input torque from the engine 12 and the engine torques from the first and second torque machines 60 . 62 are generated as a result of energy conversion of fuel or electric potential stored in the battery. The battery is DC coupled to the power converter module via the high voltage electrical bus. The power converter module preferably comprises a pair of power converters and respective motor control modules configured to receive and command torque converter commands, and thus provide motor drive or recuperation functionality to comply with engine torque commands. The power converters include complementary three-phase power electronics and each includes a plurality of insulated gate bipolar transistors (IGBTs) for converting DC power from the battery to AC power for energizing each of the first and second torque machines 60 and 62 by switching to high frequencies. The IGBTs form a switching power supply configured to receive control commands. Each phase of each of the three-phase electric machines includes a pair of IGBTs. States of the IGBTs are controlled to provide mechanical motor drive power generation or electrical energy recuperation functionality. The three-phase power converters receive or supply DC electrical power via DC transmission conductors and convert them into or out of three-phase AC power supplied to or from the first and second torque machines 60 and 62 for operation as motors or generators via transmission line is passed. The power converter module transmits electrical power to and from the first and second torque machines 60 and 62 by the power converters and respective motor control modules in response to the engine torque commands. Electric power is transmitted to and from the battery via the high voltage electric bus to charge and discharge the high voltage battery.

The controller 5 is with various actuators and sensors in the powertrain system via a communication link 15 technically and functionally linked to monitor and control the operation of the powertrain system, synthesizing information and inputs, and executing algorithms to control actuators, and thus achieve control objectives related to fuel economy, emissions, performance, driveability and protection of components, the cells of the high voltage battery and the first and second torque machines 60 and 62 include, are related. The controller 5 is a subset of an overall controller architecture of the vehicle and provides a coordinated system control of the powertrain system. The controller 5 may include a distributed control module system including individual control modules including a supervisory control module, an engine control module, a transmission control module, a battery pack control module, and the power converter module. A user interface is preferably signaled to a plurality of devices by which a vehicle operator directs and commands the operation of the powertrain system, including commanding an output torque request and selecting a transmission range. The devices preferably include an accelerator pedal, an operator brake pedal, a transmission range selector (PRNDL), and a vehicle speed control system. The transmission range selection means may comprise a discrete number of operator-selectable positions indicating the direction of the operator's intended movement of the vehicle and thus indicating the preferred direction of rotation of the output member 92 of either a forward or a reverse direction. It should be noted that the vehicle is due to a roll back, which is due to the position of the vehicle, for. B. on a mountain, can still move in a different direction than the specified, intended by the operator movement direction. The operator-selectable positions of the transmission range selector may correspond directly to individual transmission ranges described with reference to Table 1 or may correspond to subsets of the transmission ranges described with reference to Table 1. The user interface may include a single device as shown, or alternatively may include a plurality of user interface devices directly connected to individual control modules.

The aforementioned control modules communicate with other control modules, sensors and actuators via the communication link 15 which effects structured communication between the various control modules. The communication protocol is application-specific. The communication connection 15 and suitable protocols provide for robust messaging and interfaces for multiple control modules between the aforementioned control modules and other control modules that provide functionality such as, e.g. B. anti-lock brakes, traction control and vehicle stability includes provide. Multiple communication buses may be used to improve communication speed and provide some degree of signal redundancy and integrity, which may include direct connections and serial peripheral interface (SPI) buses. Communication between individual control modules may also be performed using a wireless connection, e.g. A wireless short-range radio communication bus. Individual facilities can also be directly connected.

Control module, module, controller, controller, controller, processor, and similar terms mean any of or various combinations of one or more of application specific integrated circuit / application specific integrated circuits (ASIC), an electronic circuit / electronic circuits, a central processing unit / central processing units (preferably a microprocessor / microprocessors) and associated memory and storage (read-only memory, programmable read only memory, Random access memory, hard disk memory, etc.) executing one or more software or firmware programs or routines, a combinational logic / combinational logic circuit, an input / output circuit and input / output devices / input / output circuits, and Input / output devices, a suitable signal conditioning and buffering circuit, and other components to provide the described functionality. Software, firmware, programs, instructions, routines, code, algorithms, and similar terms mean any instruction set including calibrations and look-up tables. The control module has a set of control routines that are executed to provide the desired functions. Routines are executed, such as by a central processing unit, to monitor inputs from detectors and other networked control modules and to perform control and diagnostic routines to control the operation of actuators. Routines may be executed at regular intervals, referred to as loop cycles, for example, every 3.125, 6.25, 12.5, 25, and 100 milliseconds during ongoing engine and vehicle operation. Alternatively, routines may be executed in response to the occurrence of an event.

The multi-mode powertrain is configured to operate in one of a plurality of powertrain states including a plurality of transmission ranges and engine states to generate torque and to the driveline 90 transferred to. The engine conditions include an ON state, an OFF state, and a fuel cut state (FCO state). When the engine is in the off state, it is not fueled, does not fire, and does not reverse. When the engine is in the on state, it is fueled, ignited, and revs. When the engine is operating in the FCO state, it overflows, but is not fueled and does not fire. The ON state of the engine may further include an all-cylinder state (ALL) wherein all cylinders are fueled and fired, and a cylinder deactivation state (DEAC) wherein a portion of the cylinders is fueled and ignited, and the remainder Cylinders should not be fueled and ignite. The transmission ranges include a plurality of ranges of neutral (neutral), gear (# #), electric vehicle (EV #), and electrically variable mode (EVT mode #) achieved by clutches C1 52 , C2 54 and C3 56 be selectively activated. The neutral range is also referred to as an electric torque converter (ETC) range during which electrical power to or from the battery may flow relative to the output torque, engine speed, output speed, and speed from one of the torque machines. There may be other powertrain conditions, eg. B. transition areas, are applied. Table 1 shows a plurality of powertrain conditions including transmission ranges and engine states for operating the multi-mode powertrain. Table 1 Area Engine state C1 C2 C3 Neutral 1 / ETC ON (ALL / DEAC / FCO) / OFF EVT mode 1 ON (ALL / DEAC / FCO) X EVT mode 2 ON (ALL / DEAC / FCO) X Festival 1 ON (ALL / DEAC / FCO) X X 2 engine EV OUT X X Motor A EV OUT X Engine B EV OUT X

wobei

Ta

einen Drehmomentausgang der ersten Drehmomentmaschine 60 darstellt,

Tb

den Drehmomentausgang der zweiten Drehmomentmaschine 62 darstellt,

Ti

das Eingangsdrehmoment an Element 14, d. h. von der Kraftmaschine 12, darstellt,

To

das Ausgangsdrehmoment an Element 92 darstellt,

Na

die Drehzahl der ersten Drehmomentmaschine 60 darstellt,

Nb

die Drehzahl der zweiten Drehmomentmaschine 62 darstellt,

Ni

die Eingangsdrehzahl an Element 14 darstellt,

No

die Ausgangsdrehzahl an Element 92 darstellt, und

A1, A2, A3, B1, B2 und B3

anwendungsspezifische skalare Werte sind, die auf der Basis der Zahnradbeziehungen ermittelt werden.

The powertrain configuration allows two power split modes of operation when the engine is on, having an input-split mode, e.g. EVT1, and a combined power split mode, e.g. B. EVT2 include. The configurations allow for that second torque machine 62 from the transmission output member 92 can be disconnected without the flow of power from the engine 12 and the first torque machine 60 to interrupt. This configuration allows the use of a shift strategy whereby transmission range changes can be accomplished by the second torque machine 62 is separated and their speed regardless of the combustion engine 12 and the output element 92 is controlled to synchronize components of an approaching clutch. When working in the Fixed 1 area, the powertrain system has a single degree of freedom (1-dF) in terms of speed. Thus, there is a single independent speed node, and all other speed nodes are linearly dependent thereon. For example, all speed nodes that include the input speed (Ni) are proportional to the output speed (No). Exemplary dominant equations include the following:

in which

Ta

a torque output of the first torque machine 60 represents,

Tb

the torque output of the second torque machine 62 represents,

Ti

the input torque to element 14 ie from the engine 12 ,

to

the output torque on element 92 represents,

N / A

the speed of the first torque machine 60 represents,

Nb

the speed of the second torque machine 62 represents,

Ni

the input speed at element 14 represents,

No

the output speed at element 92 represents, and

A1, A2, A3, B1, B2 and B3

are application-specific scalar values, which are determined on the basis of the gear relationships.

wobei

A11, A12, A21, A22, B11, B12, B21 und B22

anwendungsspezifische skalare Werte sind, die auf der Basis der Zahnradbeziehungen ermittelt werden.

When operating in any of the EV or EVT ranges, the powertrain system has two degrees of freedom (2-dF) in terms of speed, allowing for two independent speed nodes. For example, all speed nodes other than the input and output speeds may be calculated as a linear combination of the input and output speeds. Exemplary dominant equations include the following:

in which

A11, A12, A21, A22, B11, B12, B21 and B22

are application-specific scalar values, which are determined on the basis of the gear relationships.

wobei

A1, A2, A3, B1, B2 und B3

anwendungsspezifische skalare Werte sind, die auf der Basis der Zahnradbeziehungen ermittelt werden.

When operating in the ETC area, the powertrain system has three degrees of freedom (3-dF) in terms of speed including the input speed, the output speed, and another speed. In this area, there can not be the flexibility to choose engine torques such that the battery power is zero for any given engine torque. If no clutches are applied, the transmission is in the ETC area. In this transmission range is the second torque machine 62 decoupled from the transmission, so that their speed can be controlled independently. The torque output Ta of the first torque machine 60 is proportional to the output torque To and its speed is a linear combination of the input and output speeds. Exemplary dominant equations include the following:

in which

A1, A2, A3, B1, B2 and B3

are application-specific scalar values, which are determined on the basis of the gear relationships.

A control scheme is employed to effect a transition to a final transmission range and powertrain conditions that includes operating the powertrain system in the ETC range to take advantage of the three degrees of freedom with respect to speed. Applying the ETC range during a shift allows transition between two of the EVT ranges while maintaining a constant speed of the engine to convey a vehicle feel perceived as supple by the vehicle operator.

2 illustrates a control scheme 100 for effecting a change from an initial transmission range to a target transmission range, which comprises applying a transmission operating range having three degrees of freedom, referred to herein as a 3-dF shift. In the referring to 1 described powertrain system, the transmission operating range, which has three degrees of freedom, the ETC area. The control scheme 100 can in any of the aforementioned controllers 5 be carried out periodically to the operation of an embodiment of the with reference to 1 to control described powertrain system. Table 2 is considered a key too 2 where the numbered blocks and the corresponding functions are as follows. Table 2 BLOCK BLOCK CONTENT 102 Commands operation in target transmission range 104 Solve Outgoing (OG) Coupling (s) 106 Operate gear in 3-dF operating mode 108 Control speed of one of the torque actuators to synchronize oncoming (OC) clutch 109 Activate OC clutch during synchronization 110 Controlling speeds of the remaining torque actuators to maintain a preferred output speed; and controlling torque outputs of at least one of the remaining torque actuators to produce output torque in response to the output torque request 112 Operate the transmission in the target transmission range in response to the output torque request

The 3-df switching, by the control scheme 100 is achieved works as follows. Initially, the powertrain system preferably operates in one of the EVT modes, e.g. One of EVT1 and EVT2 for reference to 1 and 2 and Table 1 described powertrain system, located transmission. The powertrain system may have transitioned to just prior to running the control scheme 100 operating in one of the EVT modes, operating in one of the EV modes, and performing an autostart operation of the engine immediately prior to executing the control scheme 100 includes. In response to a command, in a target transmission range ( 102 ), disconnect (s) the clutch (s) associated with a current operating range, or otherwise disable ( 104 ) permitting operation of the transmission in an operating mode having three speed degrees of freedom (3-dF) ( 106 ). Operating the powertrain system in transmission in an operating mode having 3-dF involves operating the transmission in the ETC range described in Table 1, thereby providing independent simultaneous speed control of the torque actuators of the powertrain system, ie, the engine 12 and the first and second torque machines 60 . 62 is allowed. This includes controlling the output of one of the torque actuators, e.g. B. the second torque machine 62 to synchronize speeds of components of an oncoming (OC) clutch associated with the target transmission range ( 108 ). The oncoming clutch can be activated when its components are synchronized ( 109 ). At the same time speeds of the remaining torque actuators, z. B. the engine 12 and the first torque machine 60 controlled to maintain a preferred output speed, and a torque output from at least one of the remaining torque actuators, e.g. The first torque machine is controlled to produce an output torque that is responsive to the output torque request ( 110 ). When the on-coming clutch is activated, the operation of the powertrain system in the target transmission range may be controlled in response to the output torque request ( 112 ). The powertrain system may then proceed to operate immediately after performing 3-df shifting on transmissions located in one of the EV modes, through the control scheme 100 achieving performing an auto-start operation of the engine.

The 3-df switching, by the control scheme 100 can achieve switching of EVT1 in EVT2 without changing the speed of the engine, e.g. B. without a spin up of the engine during an auto-start operation. This includes auto-starting the engine when the vehicle is running at medium speed, e.g. B. 80 km / h (50 mph) works. The initial transmission range is EV1 with clutch C1 activated and the engine operating at zero speed. The engine is started and controlled to operate at 1400 rpm. The first torque machine operates at a positive speed. The propulsion torque is transferred to be provided by the engine and the first torque machine with the torque output from the second torque machine being zero. In this transmission range, the maximum output torque is similar to the ability in EVT2. Clutch C1 is deactivated and the speed of the second torque machine is reduced to synchronize the speed of clutch C2, at which time clutch C2 can be engaged. The torque management may be adjusted to be provided exclusively by the first torque machine having a combined torque split, wherein the torque output is provided by both the first and second torque machines. Once started, the engine may continue to operate at 1400 RPM throughout the shift to avoid overspeeding of the engine that may occur during a synchronous transition.

The 3-df switching, by the control scheme 100 can be performed to effect an upshift of EVT1 in EVT2, the second torque machine operating at a zero torque point. The initial transmission range is EVT1 with clutch C1 activated. The vehicle accelerates in EVT1 with the engine operating at peak power (in one example at 5500 RPM and 150 Newton meters operating speed), the first torque machine generating electrical power, and the second torque machine consuming electrical power. At low speeds, the speed of the first torque machine is negative. When the vehicle accelerates, the Speed of the engine is kept at a constant speed, the speed of the first torque machine decreases to zero. The vehicle continues to accelerate until the first torque machine consumes all available battery power and the torque output of the second torque machine is zero. At this point clutch C1 is deactivated and the speed of the second torque machine is reduced to synchronize the speed of clutch C2, at which time clutch C2 can be engaged. The torque management may be adjusted to be provided exclusively by the first torque machine having a combined torque split, wherein the torque output is provided by both the first and second torque machines.

The 3-df switching, by the control scheme 100 is reached, the time to perform switching can be reduced as compared with a shift execution scheme that operates with two degrees of freedom to perform a shift. There is also a reduction in the interruption of output torque during 3-dF switching. The 3-df switching, by the control scheme 100 eliminates a need for energy dissipating couplings, allowing the use of other coupling technologies. Such an operation also allows transitions between the EVT areas while maintaining a constant speed of the engine. The implementation of 3-dF shifting allows engine on-off transitions to occur at higher vehicle speeds, thereby increasing fuel economy and EV driveability. The implementation of the 3-dF shift allows the peak torque of the second torque machine to increase, which may offset a reduction in the maximum torque requirements for the first torque machine, thereby allowing for a reduction in the physical size and cost of the first torque machine. Such a procedure precludes a need to make a transition from an input-split region to a combined-split region at a synchronous operating point, thereby eliminating a need to perform a gearshift at a synchronous operating point. Such a process also means that the switching execution of the 3-dF switching is less perceptible to the operator. The 3-df switching, by the control scheme 100 can be performed as part of an overall scheme for performing switching from a first EVT area to a second EVT area and immediately following transition to an EV area. The 3-df switching, by the control scheme 100 may be performed as part of an overall scheme for performing switching from an EV region to a first EVT region and immediately following transition to a second EVT region.

3 FIG. 4 graphically illustrates operating parameters associated with an embodiment of the powertrain system described with reference to FIG 1 has been described and involves performing a 3-df switching. An embodiment of the 3-dF switching will be described with reference to the control scheme 100 from 2 described. Operating data includes data associated with performing 3-dF switching to effect an up-shift of EVT1 in EVT2, as compared to data associated with performing synchronous switching of EVT1 in EVT2. The upper section of 3 shows the device speed (RPM) on the vertical axis 304 in relation to the vehicle speed (km / h) on the horizontal axis 302 , and a temporally corresponding lower portion shows torque output (Nm) on the vertical axis 306 in relation to the vehicle speed (km / h) on the horizontal axis 302 ,

There is a plurality of speeds and torques associated with the execution of a synchronous shift, which is the speed of the engine 312 , the speed of the first torque machine 314 , the speed of the second torque machine 316 , the speed of the output element 318 , the torque of the engine 332 , the torque of the first torque machine 334 and the torque of the second torque machine 336 include. The synchronous switching of EVT mode 1 in EVT mode 2 is shown as being at time 303 is executed when the rotational speed of the first torque machine 314 is zero, thereby allowing simultaneous deactivation of clutch C1 and activation of clutch C2. In response to the execution of the synchronous shifting, the rotational speed of the second torque machine decreases 316 but there is a substantial increase in the torque of the first torque machine 334 which is required to effect the shifting while the speed of the output member 318 is kept at a constant level. As shown, the torque of the first torque machine increases 334 torque output from 70 Nm to over 100 Nm to effect this change. Thus, the first torque machine must be designed to be able to achieve this torque output in a system employing only synchronous circuits, whereas there is no such requirement for a powertrain system employing a multi-mode transmission which employs a Embodiment of a control scheme 100 for effecting a change from an initial transmission range to a target transmission range configured to perform 3-DF circuits.

There is a plurality of speeds and torques associated with the execution of a 3-dF shift, which is the speed of the engine 322 , the speed of the first torque machine 324 , the speed of the second torque machine 326 , the speed of the output element 328 , the torque of the engine 342 , the torque of the first torque machine 344 and the torque of the second torque machine 346 include. The 3-dF switching is shown as being at time 305 begins when clutch C1 is deactivated and at time 307 ends when clutch C2 is activated. At the time 305 is the speed of the second torque machine 326 able to substantially decrease without the torque of the first torque machine 344 or the torque of the second torque machine 346 affect the speed of the output element 328 to maintain at a constant level and thus to minimize driveline disturbances associated with the shift execution. Thus, an embodiment of a powertrain system that employs a multi-courage gear configured to perform 3-dF circuits may be constructed to be a first torque machine as compared with an embodiment of the powertrain system that performs synchronous shifting 60 with a reduced maximum torque capacity and a second torque machine 62 having an increased maximum speed.

The disclosure has described certain preferred embodiments and modifications thereto. Other modifications and alterations may become apparent to third parties when reading and understanding the description. Therefore, it is intended that the disclosure not be limited to the particular embodiment (s) disclosed as the best mode contemplated for carrying out this disclosure, but that the Disclosure will include all embodiments falling within the scope of the appended claims.

Claims (10)

A method of operating a powertrain system including a multi-mode transmission configured to transmit torque among an engine, first and second torque machines, and an output member in one of a plurality of transmission ranges, the method comprising: Performing a gearshift between an electrically variable initial transmission range (EVT range) and an EVT target range, comprising: Transferring to operate with three speed degrees of freedom controlling the speed of the second torque machine to synchronize the speed of an oncoming clutch associated with the target EVT range and simultaneously controlling speeds of the first torque machine and the first speed range Engine comprises, in order to achieve a preferred speed of the output element of the transmission, Controlling the torque output from the first torque machine in response to an output torque request, and Activating the oncoming clutch after synchronizing the speed of the oncoming clutch; and then Operating the powertrain system in the EVT target area. The method of claim 1, further comprising transferring the powertrain system to operate in an EV range in response to the output torque request following operation of the powertrain system in the EVT target range. The method of claim 2, wherein transferring the powertrain system to operate in the EV range comprises performing an auto-stop maneuver of the engine. The method of claim 1, wherein transitioning to operate with three speed degrees of freedom comprises deactivating an outgoing clutch in the multi-mode transmission. The method of claim 1, further comprising operating the powertrain system in an electric vehicle area (EV area) immediately prior to performing the gear shift between the EVT start area and the EVT destination area. A method of controlling a multi-mode transmission in response to a command to perform switching between a first electrically variable transmission range (EVT range) and a second EVT range, comprising: transitioning the multi-mode transmission to three speed degrees of freedom to work; Controlling torque output from a first torque machine coupled to the transmission in response to an output torque request; Controlling the speed of the second torque machine to synchronize the speed of an oncoming clutch associated with the second EVT range, and simultaneously controlling the speed of the first torque machine and controlling the speed of an engine coupled to the transmission by one to achieve preferred speed of an output element of the transmission; Activating the oncoming clutch after synchronizing the speed of the oncoming clutch; and then operating the transmission in the second EVT range in response to the output torque request. The method of claim 6, further comprising transitioning the multi-mode transmission to operate in an electric vehicle range (EV range) in response to the output torque request following operation of the powertrain system in the second EVT range. The method of claim 7, wherein transitioning the multi-mode transmission to operate in the EV range comprises performing an auto-stop maneuver of the engine. The method of claim 6, wherein transitioning the multi-mode transmission to operate at three speed degrees of freedom comprises deactivating a clutch in the multi-mode transmission. The method of claim 6, further comprising operating the multi-mode transmission in an electric vehicle area (EV area) immediately prior to performing gear shifting between the first EVT area and the second EVT area.

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